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Howlett" , Jann Horn , Pedro Falcato , David Hildenbrand , Jakub Matena , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [REGRESSION] mremap() fails VMA expansion when VM_MIXEDMAP is set Message-ID: References: <20261023023106.515365-1-luizcap@redhat.com> <8c53e58c-f7d2-4e98-8d03-7ff1163c1159@kernel.org> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8c53e58c-f7d2-4e98-8d03-7ff1163c1159@kernel.org> X-Rspamd-Queue-Id: D038D100004 X-Stat-Signature: xkbdhs31wcktw4xg7inu57ceje4s7yuo X-Rspamd-Server: rspam04 X-Spam-Status: No, score=-6.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=no autolearn_force=no version=4.0.1 X-Rspam-User: X-HE-Tag: 1792743601-845191 X-HE-Meta: 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 kMyjLxAt LCaFgsfZIF2Q3wCW3xN+ciPxtlr+dE5Zeb7SvR2qbUz+N/dLsH3AvhNoG5p1IeZBjji7RgkGQM6pPNLFs0xH2oplVfUTLtPrl6vQjARU75PwYxlqjyQWph6CGfLKRQgmJPRrnvJsE6ZxESaQNnKU/gXLdiLt7F1ViFbQMqc7l52NLtqbaf+y+L/kTWC/jjVJFWIpNDLi3tEiP3MeB+gU/eDQqALf+FP7r7rDHcTlHWw6v/5nwVJWj4IP9J+i+3X2b7MYnhvjo0/PInDE0unTKg3CCzNwsik2Plcv42Y6Hz6xa14U= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Fri, Oct 23, 2026 at 09:16:12AM +0200, Vlastimil Babka (SUSE) wrote: > On 10/23/26 04:31, Luiz Capitulino wrote: > > This regression was introduced in v6.1 by commit ca3d76b0aa80 ("mm: add merging > > after mremap resize"). This commit changed mremap() to use vma_merge() instead > > of vma_adjust() for the expansion case. However, vma_merge() returns NULL for > > a VMA that has any of the VM_SPECIAL flags set. > > Hi, > > 6.1 was a rather long time ago. How was it discovered just now? I.e. what > use case broke by the change and prompted creating the reproducer? > > Vlastimil > Thanks, Thanks, I have the same questions :) Do always include that kind of information and whether it was an LLM-discovered thing or whether you had an actual workload that was impacted, etc. -- Cheers, Lorenzo